Use pbx_variable_new instead of ast_variable_new. Fix segfault when running 'sccp reload force' after running 'sccp reload device ...', because of errornous pbx_variables_destroy of GLOB(cfg) during 'sccp reload device ...', which should only happen for realtime devices.

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4900 43c1dc8c-776e-4df2-8ef1-6e829299be21